A dual modulation display provides increased local peak brightness and reduced overall brightness. Each pixel of the display can have high peak brightness, e.g., 400-1000 nits or even more. However, most pixels during a display operation may only need to be rendered at a much lower brightness, e.g., 100 nits or even less. A display, capable of generating 400-1000 nits across the full screen, unnecessarily employs expensive components for each pixel to achieve high local peak brightness, and generates an excessive amount of heat from underutilized, over-provisioned optical energy.
Small display systems such as mobile devices may not have sufficient room to install a large number of active light emitting elements. However, a low-fill factor single board capable of providing relatively uniform full screen lighting may be costly to make or install, especially in a small form factor device in which space availability is at a premium. Further, multiple low-fill factor lighting modules assembled together for full screen lighting often exhibit undesirable visual artifacts such as visually perceptible lines, shadows and non-uniformity in the border regions of the multiple lighting modules and/or in other regions such as occupied by on-board circuitry. Additional components such as light diffusers can be installed to ameliorate or reduce the undesirable visual artifacts, thereby leading to larger and heavier form factors for mobile devices.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued by others. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.